Sustainable color stripping of cotton substrate dyed with reactive dyes in a developed UV/K2S2O8 photocatalytic system

An efficient, sustainable and energy conservation system and method for color stripping of reactive dyes on cotton substrate in a dipping manner were constructed for the first time via a UV irradiation of potassium persulfate (K2S2O8) in aqueous system to photocatalytically generate working species at an ambient temperature. The results show that the active species in the developed UV/K2S2O8 system could efficiently attack and decolorize the model dye as well as other applied reactive dyes after being fixed on cotton substrate with high selectivity. An efficient and significant improvement of color stripping was available with a color stripping ratio higher than 90.0% even at a stripping duration of 30.0 min. High efficiencies in color stripping of 14 commercial reactive dyes involving various chromophoric matrixes on cotton substrate were also achieved in the stripping system with a recommended process, accompanied with commercially satisfactory tensile strength retentions of the substrate. The color stripping on the substrate in the UV/K2S2O8 system was further traced and explored successfully by Fourier transform infrared spectrometry (FT-IR) and scanning electron microscopy (SEM) analysis. Additionally, a possible working mechanism of the developed system for color stripping on the substrate was also proposed. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.